Dehydroabietic acid and ethylene reaction products

ABSTRACT

New compositions of matter are prepared by reacting ethylene with dehydroabietic acid (or disproportionated rosin) in the presence of palladium (II) acetate to give mixed dimeric dibasic acids.

United States Patent [191 Schuller [451 Sept. 10, 1 974 DEHYDROAB IETICACID AND ETHYLENE REACTION PRODUCTS [75] Inventor: Walter H. Schuller,Lake City, Fla.

[73] Assignee: The United States of America as represented by theSecretary of Agriculture, Washington, DC.

22 Filed: Sept. 13,1972

21 Appl. No.: 288,807

52 U.S.Cl 260/4685, 260/75 UA, 260/5145 [51] Int. Cl. C07c 63/46 [58]Field of Search 260/5145 [56] References Cited OTHER PUBLICATIONSFujiwara, et a1., Aromatic Substitution of Olefins, (1969), JACS, 91,pp. 7166-7169.

Primary ExaminerLorraine A. Weinberger Assistant ExaminerMichae1 Shippen4 Claims, N0 Drawings DEHYDROABIETIC ACID AND ETHYLENE REACTION PRODUCTSpreparation of new compositions of matter by reacting ethylene anddehydroabietic acid of the like in the presence of palladium (l 1)acetate or mixtures thereof. By the process of this invention mixeddimeric basic acids are obtained. These products are useful in thepreparation of modified styrenated laminating polyesters.

The main object of this invention is to provide a process for thepreparation of the new compositions of matter described herein utilizingpalladium (11) acetate.

Another object of this invention is to provide a process for thepreparation of these and other compositions of matter utilizing amixture of palladium (1 1) acetate and salts such as silver acetate orcupric acetate in a solvent system containing a fatty acid such asacetic, for example, to yield rosin-based mixed dimeric dibasic acids.

In Tetrahedron Letters, 35 p 3863 (1968) and Journal of AmericanChemical Society, 91, p7166 (1969), the reaction of ethylene withbenzene in the presence of palladium (11) acetate is described. In theJACS article, on page 7167, it was stated that other two-step arylationreactions have not been found in our limited work with olefins. This hasreference to the reaction of the styrene initially formed in thereaction wih another mole of benzene to give stilbene. When toluene wasused in place of benzene lower yields of the analogous products wereobtained (ref. the Tetrahedron Letters).

In investigating the prior art it was determined that dehydroabieticacid (1) might be too heavily substituted COOH I The GLC analysesemployed in these investigations were carried out as developed for theanalysis of rosinbased dimeric dibasic acids produced by the sulfuricacid catalyzed isomerization of abietic acid and various rosins,reported in Industrial & Engineering Chemistry,

Product Research and Development, 9, page 60 (1970). The GLC curves ofthe ethylenedehydroabietic acid reaction mixtures and the reactionmixtures from the sulfuric acid catalyzed dimerization of abietic acidwere similar but not identical. Monomeric resin came off isotherrnallyat C. On subsequent programming at 30C/minute to 360C, the mixeddibasic-dimeric rosin based acids (as the esters) then came off of thespecially prepared air oxidized silicone column.

When this investigation was repeated but employing cupric acetate inplace of silver acetate a 29 percent yield of mixed dimeric dibasicacids was obtained. When a blank run was made in the absence of ethyleneno appreciable amount of mixed dimeric dibasic acid was observed.

In the preparation of mixed dimeric dibasic resin acids from ethyleneand dehydroabietic acid in the presence of palladium acetate and silveracetate the monomer peak consisted of essentially all unreacteddehyroabietic acid, which obviously could be recycled through theprocess. The catalysts also could be rei worked. For example, thepalladium metal is easily regenerated in essentially quantitative yieldto give palladium (l1) acetate upon boiling in acetic acid mixed with asmall quantity of nitric acid.

Further investigative efforts were made and it was found thatdisproportionated or dehydrogenated rosin which contained highproportions of dehydroabietic acid could also be employed as thestarting materials, rather than pure dehydroabietic acid. A method forpreparing pure dehydroabietic acid or a dehydrogenated rosin containinga high proportion of dehydroabietic acid is reported in the Journal ofOrganic Chemistry,-31, page 426 (1966).

The yields of mixed dimeric dibasic resin acids from the reaction ofethylene and dehydroabietic acid are much higher when a mixture ofhydrocarbon solvents such as n-heptane and acetic acid are used ratherthan when only n-heptane or only acetic acid is used as the solvent forthe reaction. Higher yields of mixed dibasic dimeric resin acids can beobtained also when salts such as silver acetate are used in conjunctionwith palladium (1 l acetate to recycle the palladium metal during thereaction; that is, higher than when palladium acetate is used alone.

Presently the mixed dimeric dibasic resin acids formed by the process ofthis invention are useful as modifiers for unsaturated polyester resinscrosslinked with styrene to give laminating resins.

The reaction discussed hereinabove can be carried out at temperaturesfrom about 40C to the reflux temperature of the solvent used or thesolvent mixture employed. The preferred temperature range is from about60C to the reflux temperature of the solvent system used.

The palladium acetate used in the hereinabove described reaction is, asis readily apparent, a reactant in the process and is used in equimolaramounts when used alone. Palladium acetate can be used in less thanequimolar amounts if salts are used in conjunction with the palladiumacetate, which are capable of regenerating the palladium formed to giverenewed amounts of palladium acetate. Such salts are, e.g., silveracetate and cupric acetate.

The following examples are provided to illustrate the preferredtechniques applicable to the process of this 3 invention and should notbe construed as altogether limiting the invention.

EXAMPLE 1 To a solution of 6.0 g (0.02 mole) of dehydroabietic acid in24 ml of glacial acetic acid and 100 ml of nheptane is added 2.25 g(0.01 mole) of palladium (11) acetate and 16.69 g (0.10 mole) of silveracetate and the mixture charged to a 500 ml r.b. four-necked flaskequipped with a reflux condenser terminated with adrying tube filledwith Drierite desiccant, a thermometer, a gas inlet tube extending belowthe surface of the liquid, and a mechanical stirrer. Ethylene gas isbubbled through the dispersion during vigorous stirring under reflux(89C) for 8 hours. The flask is heavily silvered at the end of thereaction and the brown dispersion has turned to a dark black dispersion.The solution is filtered, water washed, stripped and the brown friablesolid residue is dried under reduced pressure over Drierite desiccant;yield 6.86 g; m.p. l54158 'd ec.; equiv. wt. 328. A portion is reactedwith an excess of ethereal diazomethane. The methyl esters are analyzedby means of GLC, being linear temperature programmedto 360C at 30C/min.using an air oxidized silicone column cured in air at 350C overnight.The yields based on dehydroabietic acid are mixed dibasic acid dimers 62percent, methyl dehydroabietate 38 percent, calculated from the GLCvolatile 'material. The :total percent GLC volatiles is 80 percent. Theyield of dimer based on palladium (1 1) acetate is about .100 percent.The UV on the crude ester mixture is A max. (95 percent ethanol) 298 ,ubroad (a 55), with peaks at 268 and 276 u.

The ultraviolet spectrum of the reaction product of ethylene anddehydroabietic acid confirmed the presence of stilbene type compounds [Amax. stilbene 295 :p. (a 150)]. The absence of peaks in the 240-250 p.re-' gion indicates the probable absence of any significant amount ofsingle step arylation reaction product [A max. styrene 244 ,u. (a 212)].

EXAMPLE 2 Example 1 is repeated using cupricacetate in twice the molaramount of silver acetate used. A 29 percent yield of mixed dibasicdimeric resin acids is obtained based on GLC analyses.

EXAMPLE 3 Example 1 is repeated with the exception that no ethylene waspassed through the solution. No significant amount of dimer is formed.

EXAMPLE 4 Example 1 is repeated using twice the amount ofdisproportionated rosin as dehydroabietic acid. The dis- .proportionatedrosin contained about 50 percent of dehydroabietic acid as determined byGLC. The disproportionated rosin is prepared according to the methoddescribed in J. Org. Chem. 31,4246 (1966). The yield of mixed dibasicdimeric resin acids is 60 percent based on the dehydroabietic contentpresent.

EXAMPLE 5 To 75 ml of glacial acetic acid is added 1.5 g ofdehydroabietic acid (.005 mole) and 2.25 g of palladium (11) acetate(.01 mole) /z mole ratio) and the mixture is charged to an apparatus asdescribed inExample l t Ethylene gas is bubbled through the dispersionduring stirring at a liquid temperature of 100C for 8.5 hours. A 10 mlaliquot is taken from the reaction mixture, filtered by gravity, etheradded, washed with water until neutral, an excess of an etherealsolution of diazomethane added, the excess reagent blown off withnitrogen after 1.5 hours and the product is analyzed via glc accordingto the procedure in Example 1. The yield of dimer acids is 8.4 percent.

EXAMPLE 6 nitrogen, an excess of ethereal diazomethane is added andallowed to stand for 1 hour, excess reagent is blown 2 5 :off undernitrogen stream, and the mixture is analyzed via glc as described inExample 1. The dimer acids content is found to be 10.3 percent by thismethod.

EXAMPLE 7 To 60 ml of glacial acetic acid in an apparatus as describedin Example 1 is added 1.5 g (0.00478 mole) of methyl dehydroabietate and1.61 g (0.0072 mole) of palladium (1 1) acetate. Heat and stirring issupplied and ethylene gas'is passed through the mixture. The liquidtemperature is held at 100C. After 8 hours the reaction is terminated. A10 ml aliquot is removed, fil- 'tered, diluted with ether, washed withwater until neutral, excess ether blown off under nitrogen stream andresidual solution analyzed via glc according to the procedure describedin Example 1. The dimer acids ester "content is 18.8 percent.

EXAMPLE 8 The mixed dibasic dimeric resin acids from Example 1 isused'to modify a styrenated unsaturated polyester laminating resin asfollows.

' A 22 gram sample of the crude mixed dimeric dibasic acid reactionproduct from Example 1 is esterified under nitrogen with 5 grams ofdiethylene glycol. The

rosin and gylcol are charged tothe pot and heated with stirring under ablanket of nitrogen to 280C. About one hour is required to reach 280C.After 6.5 hours the ester has an acid number of 28. The temperature isthen dropped to 190C and fumaric acid (26 g) and diethylene glycol(25 g)are added. Hydroquinone in the amount of 0.01 percent is added and thecharge heated at 190195C under a light nitrogen sweep for 9 hours. Arosin modified unsaturated polyester of acid no. 26 is obtained. Thepolyester gave a clear solution on 25 percent dilution with styrene. A25 percent solution in styrene has a Gardner viscosity of Z-6. A 35percent solution has a viscosity of R. On curing between chrome platesusing 1.5 percent benzoyl peroxide for 4 hours at C and 2 hours at C,the 25 percent dilution hasa Barcol hardness of 41 and the 35 percentdilution I a Barcol hardness of 45. Chemical tests on the two laminatingresins are as follows:

Percentage Weight Gain Barcol Hardness 25% Styrene 24 Air dried 24 Airdried B.H. Start 40 Hrs. Week 14 days Hrs. Week 14 days Water 0.2330.752 0.508 36 30 28 NaOH 0.114 0.372 0.357 35 32 30 30% H- SO, 0.2450.455 0.354 38 33 38 50% EtOH 0.458 1.649 1.036 28 13 28 Toluene 1.220l8 0 0 35% Styrene ifl. Start 42 Water 0.231 0.614 0.471 41 38 38 10%NaOH 0.171 0.557 0.342 40 3s 38 30% H 80 0.133 0.346 0.257 40 38 38 50%EtOH 0.219 0.735 0.344 40 34 38 Toluene 0.045 0.537 0.431 43 33 42 Weclaim: tionated rosin containing about 50 percent dehy- 1. A mixture ofdimeric dibasic acids prepared by the reaction of a dehydroabieticacid-containing resin with ethylene in a mixture of glacial acetic acidand nheptane and catalyzed by a catalyst selected from the groupconsisting of palladium (l l) acetate, silver acetate, and cupricacetate, or a combination of any two of these.

2. The mixed dimeric dibasic resin acid composition produced by:

a. mixing 0.01 mole of palladium (l1) acetate, 0.10

mole of silver acetate, and 0.02 mole dehydroabietic acid in a 1:4 byvolume mixture of glacial acetic acid and n-heptane to obtain a percentdispersion,

b. stirring the 20 percent dispersion vigorously in a vessel equippedwith reflux condenser,

c. bubbling ethylene gas through the dispersion during the vigorousstirring under reflux for about 8 hours,

d. separating the brown friable solid formed from the charge, and

e. drying the solid under reduced pressure over a desiccant.

3. The mixed dimeric dibasic resin acid composition produced by:

a. mixing 0.01 mole of palladium (1 l) acetate, 0.10

mole of silver acetate, and 0.04 mole of dispropordroabietic acid in a1:4 by volume mixture of glacial acetic acid and n-heptane to obtain a40 percent dispersion,

b. stirring the 40 percent dispersion vigorously in a vessel equippedwith reflux condenser,

c. bubbling ethylene gas through the dispersion during the vigorousstirring under reflux for about 8 hours,

d. separating the brown friable solid formed from the charge, and

e. drying the solid under reduced pressure over a desiccant.

4. The mixed dimeric dibasic resin acid ester composition produced by:

a. mixing 0.0072 mole of palladium (1 l) acetate and 0.00478 mole methyldehydroabietate in glacial acetic acid to obtain a 5 percent dispersion,

b. stirring the 5 percent dispersion vigorously in a vessel equippedwith reflux condenser,

c. bubbling ethylene gas through the dispersion during the vigorousstirring and heating at C for about 8 hours,

(1. separating the brown friable solid formed from the charge, and

e. drying the solid under reduced pressure over a desiccant.

2. The mixed dimeric dibasic resin acid composition produced by: a.mixing 0.01 mole of palladium (11) acetate, 0.10 mole of silver acetate,and 0.02 mole dehydroabietic acid in a 1:4 by volume mixture of glacialacetic acid and n-heptane to obtain a 20 percent dispersion, b. stirringthe 20 percent dispersion vigorously in a vessel equipped with refluxcondenser, c. bubbling ethylene gas through the dispersion during thevigorous stirring under reflux for about 8 hours, d. separating thebrown friable solid formEd from the charge, and e. drying the solidunder reduced pressure over a desiccant.
 3. The mixed dimeric dibasicresin acid composition produced by: a. mixing 0.01 mole of palladium(11) acetate, 0.10 mole of silver acetate, and 0.04 mole ofdisproportionated rosin containing about 50 percent dehydroabietic acidin a 1:4 by volume mixture of glacial acetic acid and n-heptane toobtain a 40 percent dispersion, b. stirring the 40 percent dispersionvigorously in a vessel equipped with reflux condenser, c. bubblingethylene gas through the dispersion during the vigorous stirring underreflux for about 8 hours, d. separating the brown friable solid formedfrom the charge, and e. drying the solid under reduced pressure over adesiccant.
 4. The mixed dimeric dibasic resin acid ester compositionproduced by: a. mixing 0.0072 mole of palladium (11) acetate and 0.00478mole methyl dehydroabietate in glacial acetic acid to obtain a 5 percentdispersion, b. stirring the 5 percent dispersion vigorously in a vesselequipped with reflux condenser, c. bubbling ethylene gas through thedispersion during the vigorous stirring and heating at 100*C for about 8hours, d. separating the brown friable solid formed from the charge, ande. drying the solid under reduced pressure over a desiccant.